A body-sized phantom for evaluation of diffusion-weighted MRI data using conventional, readout-segmented, and zoomed echo-planar sequences

Toni Ihalainen; Linda Kuusela; Maiju Soikkeli; Eila Lantto; Ali Ovissi; Outi Sipilä

doi:10.1177/0284185115613652

A body-sized phantom for evaluation of diffusion-weighted MRI data using conventional, readout-segmented, and zoomed echo-planar sequences

Acta Radiol. 2016 Aug;57(8):947-54. doi: 10.1177/0284185115613652. Epub 2015 Nov 5.

Authors

Toni Ihalainen¹, Linda Kuusela², Maiju Soikkeli³, Eila Lantto⁴, Ali Ovissi⁴, Outi Sipilä⁵

Affiliations

¹ HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland Department of Physics, University of Helsinki, Helsinki, Finland toni.ihalainen@hus.fi.
² HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland Department of Physics, University of Helsinki, Helsinki, Finland.
³ Department of Chemistry, University of Helsinki, Helsinki, Finland.
⁴ HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
⁵ HUS Medical Imaging Center, Clinical Physiology and Nuclear Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.

PMID: 26543056
DOI: 10.1177/0284185115613652

Abstract

Background: Abdominal diffusion-weighted imaging (DWI) has been rapidly increasing during the last few years. For the evaluation of new DWI techniques, the development of suitable phantoms and quality assurance methods is important.

Purpose: To construct a body-diameter phantom for abdominal DWI and study the impact of different acquisition options on image quality.

Material and methods: A phantom with a diameter of 31 cm and a volume of 26 L was constructed, containing four samples representing a clinically relevant range of apparent diffusion coefficient (ADC) values. Measurements were carried out on 1.5T and 3.0T MRI systems using conventional echo-planar imaging (EPI), readout-segmented EPI, and zoomed EPI (3.0T) sequences. The effects of parallel imaging, coil intensity normalization, and patient-specific B1 shim (3.0T) were also examined. ADC values and signal-to-noise ratios of the samples were measured, and the level of artifacts was visually evaluated.

Results: The agreement of ADC values between different acquisition options was generally good, but higher values (by 0.07 × 10(-3) mm(2)/s on the average) with readout-segmented EPI as well as ADC variations of approximately 0.1 × 10(-3) mm(2)/s in slice direction were observed. The image artifacts were reduced by using patient-specific B1 shim, readout-segmented EPI, or zoomed EPI.

Conclusion: The body-sized phantom demonstrated well the expected image artifacts in DWI with large field of view. The use of patient-specific B1 shim, readout-segmented EPI, or zoomed EPI improved image quality of DWI in this study.

Keywords: Magnetic resonance (MR) diffusion/perfusion; imaging sequences; quality assurance/quality control (QA/QC).

MeSH terms

Abdomen / diagnostic imaging*
Artifacts
Diffusion Magnetic Resonance Imaging / methods*
Echo-Planar Imaging / methods
Equipment Design
Humans
Phantoms, Imaging*
Signal-To-Noise Ratio